CODEWITHSUNDEEP
iosswiftswift2key-value-observing
John Doe
John Doe

Reputation: 821

How to properly add Key-Value Observer to my button?

I have a UITableViewCell file and inside of it I do: 

var followers: FollowersModel? {
    didSet { 
        self.followerButton.addObserver(self, forKeyPath: "followerButtonTapped", options: .New, context: &kvoContext)
    }
}

override func observeValueForKeyPath(keyPath: String?, ofObject object: AnyObject?, change: [String : AnyObject]?, context: UnsafeMutablePointer<Void>) {
    print(keyPath)
}

where 

private var kvoContext = 0

So, I want: When I click on the button in those Cell it'll run function from the ViewController. But on click on my button does not print anything.

It's my first time with KVOs, am I doing something wrong?

Upvotes: 2

Views: 1413

Answers (1)

Mikhail Vasilev
Mikhail Vasilev

Reputation: 1167

Well, KVO does not work like that. What - addObserver:forKeyPath:options:context: does is register observer to receive KVO notifications when property changed. In your case I suppose "followerButtonTapped" is not a property. Registering for observation

To handle button tapped you need to add target like this (or in IB):

cell.followerButton.addTarget(self, action: #selector(ViewController.onFollowerButtonTap(_:)), forControlEvents: .TouchUpInside)

And add method to your view controller:

func onFollowerButtonTap(sender: UIButton) {

}

To get the model object for this button you can use this extension:

extension UITableView {
    func indexPathForView(view: UIView) -> NSIndexPath? {
        let hitPoint = view.convertPoint(CGPoint.zero, toView: self)
        return indexPathForRowAtPoint(hitPoint)
    }
}

Upvotes: 1

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